Technical Field
The present invention relates to a device for filling a container, and in particular a piston filler, which is provided for use in a rotary foodstuff filling plant in several embodiments.
Related Art
In order to fill viscous foodstuffs or beverages, in particular high viscosity foodstuffs such as for example jams, yogurts, ketchups, mayonnaise, cream etc., it is known to carry out the filling of the high viscosity foodstuffs by means of piston fillers. Piston fillers are also used for filling viscous foodstuffs that contain solids, such as for example pieces of fruit or chocolate, cereals, or other solids that are filled in conjunction with foodstuffs.
The use of piston fillers for filling viscous fill product has the advantage that the viscous fill products, which would otherwise not flow out, or would flow out only very slowly, can be dispensed into the containers that are to be filled at a specified speed corresponding to the timing of the applicable filling plant. Furthermore, by using the dosing piston of the piston filler it is possible to achieve precisely dosed filling, so that the fill product can be introduced with the intended fill volume, fill weight or fill height into the containers to be filled.
Various configurations of piston fillers are known. From DE 24 53 312 A1, for example, a rotary piston filler is known in which the flow of the fill product from a fill product reservoir into the dosing cylinder is controlled by means of a plunger that is provided with an appropriate valve opening. In this case the plunger serves both as a valve for controlling the flow of fill product and as a discharge plunger for expelling residues of fill product from the discharge channel.
From JP 200-308470 A1, a piston filler is known in which a rotary valve disposed below the fill product reservoir controls the flow of fill product between the fill product reservoir, the dosing cylinder and the discharge channel. The rotary valve has a horizontally oriented axis of rotation.
Additionally known, for example under the designation Viscofill V from KRONES AG, is a piston filler which uses a rotary valve with a vertically oriented axis of rotation for controlling the flow of fill product from a fill product reservoir into a discharge channel.
Further known, for example under the designation Viscofill S from KRONES AG, is a piston filler in which a pneumatically actuated seat valve for controlling the flow of fill product from the fill product reservoir into the dosing cylinder is provided in the base of the fill product container, and below the dosing cylinder another seat valve is provided, through which the fill product can flow out into the container that is to be filled.
The known piston fillers which have rotary valves oriented vertically or horizontally require elaborate cleaning, since each rotary valve must be removed completely from its valve seat for every cleaning procedure, for example by extracting the rotary valve from a corresponding rotary valve housing. In addition, twice in each and every dosing procedure the rotary valves are rotated by approximately 180°, which may result, depending on the fill product that is filled, in increased wear.
Furthermore, in the known systems the passages to the respective dosing cylinders are located in the frame of the product hopper. Because of this, the product can be sucked into the dosing cylinder only up to the top of the passages, with the result that it may be necessary to discard fill product from the base area of each fill product reservoir at the end of the filling process.
In the known piston dosers or fillers with seat valves, the free passage diameter for the fill product that is to be dosed is determined by the annular gap in the valves, with the result that the maximum particle diameter is limited. In addition, due to the fact that the seat valve is provided at the fill product outlet, when fill products containing solids are filled it is not possible to achieve defined division of the solids. Instead, solids can be trapped or squashed in the seating of the valve between the valve body and the valve seat, which can detract from the quality of the fill product and lead to subsequent dripping or uncontrolled falling of the squashed residues of solids.